The origin and loss of the ubiquitin activating enzyme gene on the mammalian Y chromosome
The origin and loss of the ubiquitin activating enzyme gene on the mammalian Y chromosome
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DOI：
10.1093/hmg/7.3.429
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发表时间：
1998-03-01
影响因子：
3.5
通讯作者：
Graves, JAM
中科院分区：
文献类型：
--
作者：
Mitchell, MJ;Wilcox, SA;Graves, JAM
哺乳动物的性染色体被认为是从一对同源的常染色体遗传下来的：定义Y染色体的睾丸决定等位基因出现，新生的X和Y染色体之间的重组受到限制，Y染色体逐渐失去其非必需的遗传功能，该模型最初是根据少数Y连锁遗传性状的出现，男性减数分裂期间X和Y染色体的配对以及，X-Y同源基因的比较分析是评价该模型有效性的一种手段。X-Y同源基因的一个研究得很好的例子是泛素激活酶基因（UBE 1），它在许多真兽目动物中与一个独特的Y连锁基因X连锁（“胎盘”）和元兽尽管如此，在人类Y染色体上还没有检测到UBE 1同源物，在这里，我们描述了对灵长类动物和原始哺乳动物鸭嘴兽中UBE 1同源物的更广泛的研究，我们的研究结果表明，UBE 1位于鸭嘴兽的X-Y配对片段，但不存在于人类Y染色体上，在灵长类谱系的进化过程中，UBE 1已经从Y染色体上丢失，因此UBE 1说明了性染色体上基因“常染色体到X特异性”进化的关键步骤。
Mammalian sex chromosomes are thought to be descended from a homologous pair of autosomes: a testis-determining allele which defined the Y chromosome arose, recombination between the nascent X and Y chromosomes became restricted and the Y chromosome gradually lost its non-essential genetic functions, This model was originally inferred from the occurrence of few Y-linked genetic traits, pairing of the X and Y chromosomes during male meiosis and, more recently, the existence of X-Y homologous genes, The comparative analysis of such genes is a means by which the validity of this model can be evaluated, One well-studied example of an X-Y homologous gene is the ubiquitin activating enzyme gene (UBE1), which is X-linked with a distinct Y-linked gene in many eutherian ('placental') and metatherian (marsupial) mammals, Nonetheless, no UBE1 homologue has yet been detected on the human Y chromosome, Here we describe a more extensive study of UBE1 homologues in primates and a prototherian mammal, the platypus, Our findings indicate that UBE1 lies within the X-Y pairing segment of the platypus but is absent from the human Y chromosome, having been lost from the Y chromosome during evolution of the primate lineage, Thus UBE1 illustrates the key steps of 'autosomal to X-specific' evolution of genes on the sex chromosomes.